1. Field of the Invention
This invention relates to a device for notifying a remaining amount of a developer accommodated in a developer accommodating unit for accomodating the developer used for developing a latent image formed on an electrophotographic photosensitive member, to a process cartridge including such a device, and to an electrophotographic image forming apparatus including such a process cartridge.
The electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming method. Electrophotographic image forming apparatuses include electrophotographic copiers, electrophotographic printers (such as laser-beam printers, LED (light-emitting diode) printers, and the like), facsimile apparatuses, word processors, and the like.
One type of process cartridge includes at least developing means and an electrophotographic photosensitive member integrally formed as a cartridge, which is detachably mounted on the main body of an electrophotographic image forming apparatus. Another type of process cartridge includes developing means, at least one of charging means and cleaning means, and an electrophotographic photosensitive member integrally formed as a cartridge, which is detachably mounted on the main body of an electrophotographic image forming apparatus. According to such a process cartridge method, since the user can detachably mount a process cartridge on the main body of an image forming apparatus, maintenance of the main body of the apparatus can be easily performed.
2. Description of the Related Art
In conventional electrophotographic image forming apparatuses using an electrophotographic image forming process, the process cartridge method, in which an electrophotographic photosensitive member and process means operating thereon are integrally formed as a cartridge that is detachably mounted on the main body of the apparatus, is adopted. According to the process cartridge method, since the user can perform maintenance of the apparatus instead of a serviceman, the operability of the apparatus can be greatly improved. Accordingly, the process cartrige method has been widely used in electrophotographic image forming apparatuses.
It is necessary to replace this type of process cartridge with a new one when an incorporated toner (developer) is completely consumed. Hence, there is an attempt to provide means for notifying a remaining amount of a toner being used (a developer-remaining-amount notifying device).